package top.vanchor.flexible.utils;

import lombok.extern.log4j.Log4j2;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

/**
 * Created by IntelliJ IDEA.
 *
 * @Author : Ding
 * @create 2022/6/15 11:47
 */
@Log4j2
public class UrlUtils {
    /**
     *
     * @param url 发送请求的URL
     * @return result 所代表远程资源的响应结果
     */
    public static String sendGet(String url) {
        return getSendMsg(url);
    }


    /**
     *
     * @param url 发送请求的URL
     * @param params 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return result 所代表远程资源的响应结果
     */
    public static String sendGet(String url, Map<String, ?> params) {
        String result = "";
        BufferedReader in = null;

        //初始化Map类型参数为字符串对象
        String paramString = "";
        paramString += "?";
        for (String key : params.keySet()) {
            paramString += key + "=" + params.get(key) + "&";
        }
        //去尾（去除尾部冗余的&）
        paramString = paramString.substring(0,paramString.length()-1);

        return getSendMsg(url+paramString);
    }


    private static String getSendMsg(String url) {
        String result = "";
        BufferedReader in = null;
        try {
            //为url拼接字符串类型参数
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            log.error("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }
}
